1. Field of the Invention
This invention relates to devices that are designed to prevent the accidental engagement of reverse gear. Specifically this invention is a device that prevents the engagement of reverse gear when a tractor vehicle is in a high speed range and also prevents the engagement of a high speed range when the vehicle is in reverse gear.
2. Description of the Prior Art
It is well known in the prior art to provide many different types of reverse gear lockout devices. In general these devices required cognizant action on the part of the vehicle operator in order to override the reverse lockout provision. This was done for safety reasons. It is undesirable for an operator to inadvertently engage reverse gear at certain times. For instance, when a vehicle is travelling in a forward direction at a significant velocity the engagement of reverse gear may contribute to high wear or fatigue of the transmission and drive line components. Also it is felt that it may be more difficult to control a vehicle which is travelling at high speed in reverse gear than it would be to control a vehicle travelling at low speed in reverse gear.
The usual type of reverse gear lockout depended on the placement of a cog, pin or plate, occasionally spring loaded, to prevent the movement of a shift lever into the reverse position.
Other types of systems to prevent the inadvertent engagement of reverse gear include the shift gate and the spring detent. The shift gate is a simple open grid that allows movement of a shift lever in only structured paths. The reverse position could only be reached after a shift lever was moved through a path by the vehicle operator. The spring detent reverse lockout device is equipped with a spring which will normally bias the shaft to the forward gear position only. There are numerous schemes for preventing the inadvertent engagement of reverse gear in a vehicle. The several contributions discussed above are only a few. However, the invention disclosed herein presents a new apparatus for preventing the engagement of reverse gear when a vehicle is in a high speed range and also for preventing the engagement of the high speed range when the vehicle is in reverse gear. The instant invention performs its function through an ingenious arrangement of components that makes the intended function extremely reliable.